1. Field of the Invention
This invention relates to an electronic device, and a control apparatus and a signal processing apparatus to be incorporated in said electronic device.
2. Description of the Related Art
Conventionally in an electronic device such as a DVD recorder, even if a user turns OFF the power (hereinafter referred to as “OFF status”) by manipulating POWER key provided on the operation panel, during the power turned ON (hereinafter referred to as “ON status”), the power of the device is not cutoff completely, for instance, to detect the power ON command, and it is thus kept in a so-called suspended state. In such suspended state, power is supplied to a microcomputer (a control apparatus) that is usually incorporated in an electronic device, wherein a CPU operation clock signal is oscillated from an oscillation circuit included in the microcomputer and thus the device is in a state in which power is being consumed. Such power consumption tends to increase due to growing volume of information to be processed by microcomputers as the electronic devices become sophisticated. Hence, it has become an issue how to reduce said power consumption. Thus, in order to reduce power consumption in a suspended state, the invention shown in Japanese Patent Application Laid-Open No. 9-191569, for instance, has been proposed. In the invention of the above Patent Document, there is proposed such a configuration that a plurality of modes are provided as operating modes of a microcomputer, and in a suspended mode, frequency of a clock signal to be oscillated from an oscillation circuit comprised in the microcomputer is lowered, thereby reducing consumed power.
Now, in the invention according to the Patent Document described above, since a device has adopted such a configuration that the power ON command is detected by the clock signal of low frequency, oscillation of the operating clock cannot be stopped even in suspended state, and detection of the power ON command will become impossible if oscillation is stopped. Thus, even in the above invention, predetermined operating power was needed to detect the command.